[PATCH] Also dump passive grabs on XF86LogGrabInfo

[Peter Hutterer]

On Thu, Oct 15, 2015 at 09:32:56AM -0700, Michael Stapelberg wrote:
> This patch is not entirely finished, I’ve marked the places that need further
> attention with TODO. Any input on these, and on the patch in general, is
> appreciated.
> 
> Listing passive grabs is useful for debugging the case where users don’t know
> why a keybinding is not consumed by a particular application (typically because
> another application is grabbing the binding).
> 
> I’ve tried to be consistent in the messages with other places that dump grabs
> or clients.
> 
> ---
>  dix/window.c                    | 108 ++++++++++++++++++++++++++++++++++++++++
>  hw/xfree86/dixmods/xkbPrivate.c |   2 +
>  include/window.h                |   1 +
>  3 files changed, 111 insertions(+)
> 
> diff --git a/dix/window.c b/dix/window.c
> index d57f320..5e15a72 100644
> --- a/dix/window.c
> +++ b/dix/window.c
> @@ -127,6 +127,7 @@ Equipment Corporation.
>  #include "compint.h"
>  #endif
>  #include "selection.h"
> +#include "inpututils.h"
>  
>  #include "privates.h"
>  #include "xace.h"
> @@ -273,6 +274,113 @@ log_window_info(WindowPtr pWin, int depth)
>      ErrorF("\n");
>  }
>  
> +static void
> +log_grab_info(void *value, XID id, void *cdata)
> +{
> +    GrabPtr pGrab;
> +    int i, j;
> +    pGrab = (GrabPtr)value;
> +
> +    ErrorF("  grab 0x%lx (%s), type '%s' on window 0x%lx\n",
> +           (unsigned long) pGrab->resource,
> +           (pGrab->grabtype == XI2) ? "xi2" :
> +           ((pGrab->grabtype == CORE) ? "core" : "xi1"),
> +           pGrab->type == ButtonPress ? "ButtonPress" :
> +           // TODO: where do DeviceButtonPress and DeviceKeyPress come from?
> +           // They are undefined when compiling.
> +           //pGrab->type == DeviceButtonPress ? "DeviceButtonPress" :

internally the server uses InternalEvents. depending on which client we send
the event to, we convert that into a XI2, XI1 or core event. so a grab
that's grabtype XI2 and type ButtonPress is a DeviceButtonPress grab.
IOW, you can skip the conditions and just check the core types here.

> +           pGrab->type == XI_ButtonPress ? "XI_ButtonPress" :
> +           pGrab->type == KeyPress ? "KeyPress" :
> +           //pGrab->type == DeviceKeyPress ? "DeviceKeyPress" :
> +           "XI_KeyPress",
> +           (unsigned long) pGrab->window->drawable.id,
> +           pGrab->device->id);
> +    ErrorF("    detail %d (mask %lu), modifiersDetail %d (mask %lu)\n",
> +           pGrab->detail.exact,
> +           pGrab->detail.pMask ? (unsigned long) *(pGrab->detail.pMask) : 0,
> +           pGrab->modifiersDetail.exact,
> +           pGrab->modifiersDetail.pMask ?
> +           (unsigned long) *(pGrab->modifiersDetail.pMask) :
> +           (unsigned long) 0);
> +    ErrorF("    device '%s' (%d), modifierDevice '%s' (%d)\n",
> +           pGrab->device->name, pGrab->device->id,
> +           pGrab->modifierDevice->name, pGrab->modifierDevice->id);
> +    if (pGrab->grabtype == CORE) {
> +        ErrorF("    core event mask 0x%lx\n",
> +               (unsigned long) pGrab->eventMask);
> +    }
> +    else if (pGrab->grabtype == XI) {
> +        ErrorF("    xi1 event mask 0x%lx\n",
> +               (unsigned long) pGrab->eventMask);
> +    }
> +    else if (pGrab->grabtype == XI2) {
> +        for (i = 0; i < xi2mask_num_masks(pGrab->xi2mask); i++) {
> +            const unsigned char *mask;
> +            int print;
> +
> +            print = 0;
> +            for (j = 0; j < XI2MASKSIZE; j++) {
> +                mask = xi2mask_get_one_mask(pGrab->xi2mask, i);
> +                if (mask[j]) {
> +                    print = 1;
> +                    break;
> +                }
> +            }
> +            if (!print)
> +                continue;
> +            ErrorF("      xi2 event mask 0x");
> +            for (j = 0; j < xi2mask_mask_size(pGrab->xi2mask); j++)
> +                ErrorF("%x", mask[j]);

probably better to print this with spaces between each, it's hard to read
otherwise.

> +            ErrorF("\n");
> +        }
> +    }
> +    ErrorF("    owner-events %s, kb %d ptr %d, confine 0x%lx, cursor 0x%lx\n",
> +           pGrab->ownerEvents ? "true" : "false",
> +           pGrab->keyboardMode, pGrab->pointerMode,
> +           pGrab->confineTo ? (unsigned long) pGrab->confineTo->drawable.id : 0,
> +           pGrab->cursor ? (unsigned long) pGrab->cursor->id : 0);
> +
> +    // TODO: dump another grab if there is pGrab->next

split the print into a helper function that takes a pGrab as argument, then
looping through is easy.

Cheers,
   Peter

> +}
> +
> +void
> +PrintPassiveGrabs(void)
> +{
> +    int i;
> +    LocalClientCredRec *lcc;
> +    pid_t clientpid;
> +    const char *cmdname;
> +    const char *cmdargs;
> +
> +    ErrorF("Printing all currently registered grabs\n");
> +
> +    for (i = 1; i < currentMaxClients; i++) {
> +        if (!clients[i] || clients[i]->clientState != ClientStateRunning)
> +            continue;
> +
> +        clientpid = GetClientPid(clients[i]);
> +        cmdname = GetClientCmdName(clients[i]);
> +        cmdargs = GetClientCmdArgs(clients[i]);
> +        if ((clientpid > 0) && (cmdname != NULL)) {
> +            ErrorF("  Printing all registered grabs of client pid %ld %s %s\n",
> +                   (long) clientpid, cmdname, cmdargs ? cmdargs : "");
> +        } else {
> +            if (GetLocalClientCreds(clients[i], &lcc) == -1) {
> +                ErrorF("  GetLocalClientCreds() failed\n");
> +                continue;
> +            }
> +            ErrorF("  Printing all registered grabs of client pid %ld uid %ld gid %ld\n",
> +                   (lcc->fieldsSet & LCC_PID_SET) ? (long) lcc->pid : 0,
> +                   (lcc->fieldsSet & LCC_UID_SET) ? (long) lcc->euid : 0,
> +                   (lcc->fieldsSet & LCC_GID_SET) ? (long) lcc->egid : 0);
> +            FreeLocalClientCreds(lcc);
> +        }
> +
> +        FindClientResourcesByType(clients[i], RT_PASSIVEGRAB, log_grab_info, NULL);
> +    }
> +    ErrorF("End list of registered passive grabs\n");
> +}
> +
>  void
>  PrintWindowTree(void)
>  {
> diff --git a/hw/xfree86/dixmods/xkbPrivate.c b/hw/xfree86/dixmods/xkbPrivate.c
> index 574590f..4b9ef33 100644
> --- a/hw/xfree86/dixmods/xkbPrivate.c
> +++ b/hw/xfree86/dixmods/xkbPrivate.c
> @@ -38,6 +38,8 @@ XkbDDXPrivate(DeviceIntPtr dev, KeyCode key, XkbAction *act)
>                  if (tmp->deviceGrab.grab)
>                      PrintDeviceGrabInfo(tmp);
>              xf86Msg(X_INFO, "End list of active device grabs\n");
> +
> +            PrintPassiveGrabs();
>          }
>          else if (strcasecmp(msgbuf, "ungrab") == 0)
>              UngrabAllDevices(FALSE);
> diff --git a/include/window.h b/include/window.h
> index 6daec85..f13ed51 100644
> --- a/include/window.h
> +++ b/include/window.h
> @@ -223,6 +223,7 @@ extern _X_EXPORT RegionPtr CreateClipShape(WindowPtr /* pWin */ );
>  
>  extern _X_EXPORT void SetRootClip(ScreenPtr pScreen, Bool enable);
>  extern _X_EXPORT void PrintWindowTree(void);
> +extern _X_EXPORT void PrintPassiveGrabs(void);
>  
>  extern _X_EXPORT VisualPtr WindowGetVisual(WindowPtr /*pWin*/);
>  #endif                          /* WINDOW_H */
> -- 
> 2.1.4
>